1. Technical Field
The present invention relates generally to an exhaust gas recirculation valve having a cam structure for a vehicle and, more particularly, to an exhaust gas recirculation valve having a cam structure for a vehicle, in which a gear unit for transmitting power to a valve unit and a valve-motion axis are arranged in a line such that the valve can be stably operated with power from a motor.
2. Description of the Related Art
Generally, in order to restrict generation of nitrogen oxides (NOx) from a vehicle engine, a portion of the exhaust gas that is cooled by an exhaust gas recirculation (EGR) valve is added to a fuel air mixture and then is fed to a cylinder.
For the recirculation of exhaust gas, an exhaust gas recirculation passage is formed between an exhaust manifold and a downstream of a throttle valve of an intake manifold and an exhaust gas recirculation valve is installed in the passage to open and close the passage.
The exhaust gas recirculation valve includes a housing that has a gas passage through which exhaust gas is introduced and discharged, a valve unit that selectively opens and closes the gas passage, a motor that generates power to operate the valve unit, and a power transmission that transmits rotation force from the motor to the valve unit.
The power transmission transmits the rotation force from the motor to the valve unit while converting the rotation force to a linear motion, so that, when the motor is driven, the valve unit is linearly moved and selectively opens and closes the gas passage.
However, a conventional exhaust gas recirculation valve has a problem in that power transmission gears in the power transmission are arranged in a misaligned manner, and a side of a rotary axis of the gear is only supported by the housing, so that an amount of power loss occurs due to side force and friction force during transmission of power from the motor and the operation is not stable, resulting in reduced reliability in opening and closing the gas passage for the recirculation of exhaust gas.
Further, in use, the power transmission is not smooth due to vibrations occurring on the rotary axis, which causes a considerable amount of power loss and frequently damages the rotary axis and gears.